In telecommunications systems, a mobile device includes hardware and software specific to a radio interface, along with subscriber specific data located in an identity module. For example, the Global System for Mobile Communications (GSM) system uses a subscriber identity module (SIM). The Universal Mobile Telephone Service (UMTS), which is a third generation wireless network standard enhancing GSM and WCDMA, uses a Universal SIM (USIM). The CDMA-2000 or CDMA-one system uses a Removable User Identity Module (R-UIM), which can all generally be referred to as SIM. The SIM can either be a smart card having physical dimensions similar to the well-known size of credit cards, or alternately can be “cut” to a much smaller format, commonly referred to as a ‘plug-in SIM”. In either case, the SIM card contains and organizes information, such as identity information identifying the subscriber as a valid subscriber, subscriber supplied information, such as telephone numbers, for example, operator specific information, and a certain subset of mobility management state information, such as information about the last public land mobile network (PLMN) in which the mobile device was registered.
Normally, without an identity module in place, a call will not be accepted on a communication network. However, the Federal Communication Commission has mandated that a phone without an identity module, or even a phone number, must be able to place emergency calls (E911) in a communication system and must have an identifier. Moreover, a receiving call center must have the ability to callback the initiating device to confirm that the emergency call was legitimately placed or for security reasons within the FCC mandated callback time, which is usually forty-five minutes. This raises problems of how to contact a device without an identity. This problem is compounded in packet-switched networks where individual packets must be addressed properly. Further, if an anonymously placed call is given a temporary identity to access a packet data network, then this opens an opportunity to the user of the anonymous device to access the network and to use services beyond the Emergency Packet Services or to use or receive services to which the subscriber is not allowed.
Techniques have recently become available for a mobile subscriber, either on GSM General Packet Radio Service (GPRS) and Enhanced Data for Global Evolution (EDGE), or on UMTS, to place an anonymous call, such as an emergency call, in either a circuit-switched or a packet-switched data domain without a SIM card. However, these techniques do not address the case where the temporarily addressed access for the anonymous device is left open after an emergency call is ended, leaving the possibility of further unauthorized access to or from the network.
In addition, future support of emergency packet data for mobile terminals raises risks of system abuse by users of this service. This service should be used only in case of emergency such as Voice over Internet Protocol (VoIP) 911 call or other value added emergency services. In packet data there is a window of opportunity to abuse the allowed context for non-emergency purposes.
Accordingly, what is needed is a method and apparatus for enabling the call connection and callback of anonymous user device in a packet-switched data domain while preventing further unauthorized use outside of the original purpose of the call. It would also be of benefit to develop a method to notify a Gateway GPRS Service Node (GGSN) that the particular context is for emergency signaling only. This allows the GGSN to configure the context so that only emergency traffic is allowed.